The present invention relates to a sheet discriminating apparatus, and more particularly to a bank note discriminating apparatus which is used in an automatic transaction apparatus or in an automatic classification/collection apparatus capable of handling band notes for judging whether a bank note can be handled by such apparatuses by detecting whether a hole exists in the bank note.
In general, in a sheet discriminating apparatus which judges the degree of damage of a bank note by detecting soiling of the bank note, the amount of light transmitted through and/or the amount reflected is determined. Based on the measured values, the sheet discriminating apparatus detects the presence of soiling on the bank note. However, if the predetermined part of the bank note has a hole in it or if it is folded, the value of the transmission signal (which represents the amount of the transmission light) is large and quite variable, thereby distorting measurements. Further, if a bank note with a hole is examined by using light reflected from the bank note, the amount of light reflected is changed considerably.